		* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: Arial, sans-serif;
            height: 100vh;
            display: flex;
            flex-direction: column;
            overflow: hidden;
        }
        
        /* 顶部标题行 */
        .header {
            height: 60px;
            background-color: #2c3e50;
            color: white;
            display: flex;
            align-items: center; 
            padding: 0 20px;
            border-bottom: 1px solid #34495e;
        }
        
        .logo {
            width: 170px;
            height: 50px;
            border-radius: 5px;
            margin-right: 15px;
            overflow: hidden;
            display: flex;
            justify-content: center; /* 水平居中 */
        }
        
        .logo img {
            width: 100%;
            height: 100%;
            object-fit: cover;
        }
        
        .title {
            flex-grow: 1;
            text-align: center;
            font-size: 20px;
            font-weight: bold;
        }
        
        /* 主内容区 */
        .content {
            display: flex;
            flex-grow: 1;
            overflow: hidden;
        }
        
        /* 左侧菜单区 */
        .menu-container {
            width: 200px;
            background-color: #34495e;
            color: white;
            display: flex;
            flex-direction: column;
            position: relative;
            transition: width 0.3s ease;
            overflow: hidden;
        }
        
        .menu-container.collapsed {
            width: 20px !important; /* 使用!important确保折叠状态优先 */
        }
        
        /* 菜单标题 */
        .menu-title {
            padding: 15px 10px;
            font-weight: bold;
            display: flex;
            align-items: center;
            text-align: center;
            justify-content: space-between;
            background-color: #2c3e50;
            cursor: pointer;
            white-space: nowrap;
        }
        
        .menu-title .toggle-icon {
            transition: transform 0.3s ease;
        }
        
        .menu-container.collapsed .menu-title {
            justify-content: center;
            padding: 15px 0;
        }
        
        .menu-container.collapsed .menu-title span:not(.toggle-icon) {
            display: none;
        }
        
        /* 一级菜单 */
        .menu-item {
            padding: 12px 15px;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: space-between;
            border-bottom: 1px solid #2c3e50;
            white-space: nowrap;
        }
        
        .menu-item:hover {
            background-color: #3d566e;
        }
        
        .menu-item.active {
            background-color: #3498db;
        }
        
        .menu-item .menu-text {
            display: flex;
            align-items: center;
        }
        
        .menu-item .menu-text i {
            margin-right: 8px;
        }
        
        .menu-item .arrow-icon {
            transition: transform 0.3s ease;
        }
        
        .menu-item.expanded .arrow-icon {
            transform: rotate(90deg);
        }
        
        .menu-container.collapsed .menu-item {
            justify-content: center;
            padding: 12px 0;
        }
        
        .menu-container.collapsed .menu-item .menu-text span,
        .menu-container.collapsed .menu-item .arrow-icon {
            display: none;
        }
        
        /* 二级菜单 */
        .submenu {
            list-style: none;
            background-color: #2c3e50;
            overflow: hidden;
            max-height: 0;
            transition: max-height 0.3s ease;
        }
        
        .menu-item.expanded + .submenu {
            max-height: 500px;
        }
        
        .submenu li {
            padding: 10px 10px 10px 35px;
            cursor: pointer;
            white-space: nowrap;
        }
        
        .submenu li:hover {
            background-color: #3d566e;
        }
        
        .submenu li.active {
            background-color: #2980b9;
        }
        
        .menu-container.collapsed .submenu li {
            padding-left: 10px;
            text-align: center;
        }
        
        .menu-container.collapsed .submenu li span {
            display: none;
        }
        
        /* 菜单宽度调节手柄 */
        .resize-handle {
            width: 5px;
            height: 100%;
            background-color: #2c3e50;
            cursor: col-resize;
            position: absolute;
            right: 0;
            top: 0;
            z-index: 10;
        }
        
        /* 右侧工作区 */
        .work-area {
            flex-grow: 1;
            padding: 20px;
            background-color: #ecf0f1;
            overflow: auto;
        }
        
        /* 加载内容样式 */
        .page-content {
            background-color: white;
            border-radius: 5px;
            padding: 20px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            min-height: calc(100% - 40px);
        }
        .center-span {
		  display: block;      /* 将span转为块级元素 */
		  text-align: center;  /* 文本水平居中 */
		  margin: 0 auto;      /* 块级元素水平居中 */
		} 